Adding a logo/header to theme

Hi all,

I've been trying to find a way to add my logo/header to the theme ishouvik_riverdashboard. However I'm not having any luck. All the documentation say's that I should put my logo into the _graphics which I have done and then it says to find the file "header_contents.php". "header_contents.php" does NOT exist. I searched for it using the search function in fileZilla and I've manually tried to locate it where it say's it should be but it's not there.

Can anyone tell me how to add my logo/header to this theme please?